Preface

The theme of aflatoxins is relevant worldwide for the risk involved to the health of not only humans but also for many animals of his interest. In that sense, this book can constitute a very useful tool to inform about food products that may be contaminated with aflatoxin, as well as the conditions under which such contamination is favored.

 In this book it is mentioned that there are four major aflatoxins: B1, B2, G1 and G2 and the toxicity is precisely in the direction B1> G1> B2> G2. Among the fungi responsible for the production of aflatoxins are Aspergillus flavus and A. parasiticus, but it is also involved fungi of the genera Petromyces and Emiricella. Aflatoxin has been found contaminating different grains such as corn, soybeans, wheat, rice, cottonseed, peanuts. Contamination of maize, peanuts and oilseeds can be considered, in terms of diet exposure, the most important worldwide. As a way to reduce health risks, most countries have established a maximum permissible range from 50 - 500 ng / kg of aflatoxin B1 in food. Several biotic and abiotic factors can determine fungal infection and growth, as well as aflatoxin production in pre-harvest. In post-harvest, temperature, availability of water, oxygen, and carbon dioxide, insect infestation and rodents, broken grains or nuts, the cleaning of the product, toxigenic fungal load, microbial competition, anti-fungal compound presence, and substrate composition are important too.

An important contribution is information on the incidence of aflatoxicosis on fish and the description of the method in order to approach the study.

Regarding the measurement and analysis of aflatoxins, in the past 40 years there has been a constant development of methods for detection and determination of aflatoxins in foods and agriculture commodities. This effort is required to be continuous in order to support the legislation, monitoring, and research. Highly efficient and sophisticated techniques have been developed in the recent years for the determination of aflatoxins in different commodities. Presently, the most commonly used methods for detection of aflatoxins are: High-Performance Liquid Chromatography, Gas chromatographic, Thin-Layer Chromatography and Enzyme-Linked Immunosorbent Assay and Fluorometric Method. Other techniques described include Ultra-Pressure Layer Chromatography, Liquid Chromatography Mass Spectrometry Camden, UVabsorption, Spectrometry, Fluorescence, Biosensors, Electrokinetics, Electrochemical

#### XII Preface

Transduction, amperometric Detection and Adsorptive Stripping voltammetry. Immunoassays and Biosensors are becoming a complementary or alternative recognized as conventional techniques for the analytical detection of mycotoxins and Aflatoxins.

It is also discussed about important information relative to damage prevention and control of aflatoxins and it is mentioned as example, that AFB1 requires reactive compound metabolic transformation to form the potent metabolite exo-8, 9 epoxide, which is able to interact with the genetic material. Various processes through this can be caused by DNA lesions, which in turn can bring mutational events. In the case of AFB1, carcinogenesis can cause damage in several organs, although the most corresponds to the presence of hepatocellular carcinoma. A strategy to cope with this induction of mutagenesis is the use of antimutagenic antigenotoxic agents in order to avoid or reduce such damage. So, take advantage of a) The knowledge on how are induced molecular and cellular AFB1 effects and how antimutagens occurs. b) Developed models for the biological detection of genotoxic damage and c) The easy detection in fruits and vegetables antimutagens.

On the other hand the characterization of genes involved in aflatoxin formation offers the opportunity to examine the molecular regulation mechanism of aflatoxin biosynthetic pathway, particularly the interaction during aflatoxin-producing fungiplants, in consequence, this process can be manipulated.

It is mentioned that interventions to reduce overall aflatoxin-induced illness can be grouped into three categories, agricultural, dietary and clinical. Agricultural interventions are applied methods that can be either on the field (pre-harvest) or in drying, storage and transportation (post-harvest) to reduce aflatoxin levels in food. The dietary and clinical interventions are considered secondary interventions by which the aflatoxin-related illness can be reduced. The safety issue is also of food products undergo detoxification treatments that could be improved by using phytochemical antimicrobial agents with potential activities.

In brief, reading the entire contents of this book or any of its sections allows having a based perspective about the detection, measurement or control of aflatoxins. Indeed, the presentation of information from different perspectives allows the reader to have a broader scope of understanding.

> **DR. Irineo Torres Pacheco**  Academic Group of Biosystems Engineering Faculty of Engineering Autonomous University of Queretaro Querétaro, Qro., Mexico

**Part 1** 

**Aflatoxin Contamination** 

**1** 

*Italy* 

Laura Anfossi, Claudio Baggiani,

Cristina Giovannoli and Gianfranco Giraudi *Department of Analytical Chemistry, University of Turin,* 

**Occurrence of Aflatoxin M1 in Dairy Products** 

Aflatoxin M1 (AFM1) is a major metabolite of aflatoxin B1 (AFB1), which is formed when animals ingest feed contaminated with aflatoxin B1. The AFB1, once ingested by the animal, is rapidly absorbed by the gastrointestinal tract and is transformed into the metabolite AFM1, which appears in the blood after 15 minutes and is then secreted in the milk by the mammary gland (Van Egmond, 1989; Battacone, et al. 2003). The amount of AFM1 which is found in milk depends on several factors, such as animal breed, lactation period, mammary infections etc… It has, anyway, been demonstrated that up to 6% of the ingested AFB1 is secreted into the milk as aflatoxin M1 (Van Egmond & Dragacci, 2001) and, because AFM1 is relatively resistant to heat treatments (Yousef & Marth, 1989; Galvano et al., 1996), it is almost entirely retained in pasteurized milk, powdered milk, and infant formula. Moreover, only a limited decrease of AFM1 content has been verified in UHT milk after long storage (Galvano et al., 1996; Martins & Martins, 2000; Tekinsen & Eken, 2008). The hepatotoxicity and carcinogenic effects of AFB1 have been clearly demonstrated, thus it has long been classified as a group 1 human carcinogen by the International Agency on Research on Cancer (IARC, 2002). Initially, the IARC classified AFM1 as a possible carcinogen for humans (group 2b) since toxicological data was limited (IARC, 1993). However, genotoxicity and cancerogenity of AFM1 have been observed in vivo, although lower than those of AFB1, and its cytotoxicity has been definitively demonstrated (Caloni et al., 2006). As a result of these and other further investigations, the IARC moved aflatoxin M1 from group 2B to

Considering that milk and milk derivatives are consumed daily and, moreover, that they are of primary importance in the diet of children, most countries have set up maximum admissible levels of AFB1 in feed (European Commission, EC, 2003a) and of AFM1 in milk, which vary from the 50 ng/kg established by the EU, to the 500 ng/kg established by US FDA (EC, 2003b; U.S. Food and Drug Administration, FDA, 2011). More restrictive MRLs have been implemented by the EU for the presence of AFM1 in baby food (EC, 2004) Regulations for aflatoxin M1 existed in 60 countries by the end of 2003, most of them being EU, and candidate EU countries, but some other countries in Africa, Asia and Latin America also apply the limit of 50 ng/kg. The higher regulatory level (500 ng/kg) is applied in the United States and in several countries in Asia and in Latin America, where it is also

Based on admissible levels, on measured values in milk obtained in various monitoring programs and on typical diets, the intake of aflatoxin M1 from milk has been calculated to

**1. Introduction** 

group 1 human carcinogen (IARC, 2002).

established as a harmonized MERCOSUR limit (FAO, 2011).
